Understanding the social and historical background of any artwork always help to maximize your museum visits. I recently visited the Getty Villa and joined the docent-lead tours. It helped me better understand Greek art and made the visit a great experience.
Japanese Art 101: http://en.wikipedia.org/wiki/Japanese_art
This site provides with an overall view of what Japanese art is. It is organized chronically which helps to understand art in a social and historical context. Just like contemporary art and renaissance art are different in the western world, Japanese art are very different depending on the time the artist lived.